<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>表单</title>
  <style>
    div {
      margin: 10px 0;
    }
  </style>
</head>
<body>

<div id="app">
  <div id="example-5">
    <select v-model="selected">
      <option disabled>请选择</option>
      <option>A</option>
      <option>B</option>
      <option>C</option>
    </select>
    <span>Selected: {{ selected }}</span>
  </div>
</div>

<script src="../lib/vue.js"></script>
<script>
  let vm = new Vue({
    el: '#app',
    data: {
      selected: ''
    }
  })
</script>


</body>
</html>